This proposal is to request support for a Keystone Symposia meeting entitled "Cell Death and Cellular Senescence," organized by Jacqueline A. Lees, Sally A. Kornbluth, and Gerard I. Evan, which will be held in Breckenridge, Colorado, from February 7 - 12, 2008. Cell death is known to play a critical role in both normal development and human disease. We have a good understanding of the proteins that constitute the apoptotic machinery as well as the signaling pathways that regulate this process. Many of these regulatory proteins can also induce cellular senescence, a state of irreversible cell arrest. After some initial speculation that cellular senescence might be primarily a phenomenon of cultured cells, there is now unequivocal evidence that cellular senescence occurs in vivo in response to both telomere erosion and oncogenic activation and, furthermore, that this plays a key role in tissue maintenance and tumor suppression. This meeting will explore the fundamental mechanisms that control cell death and cellular senescence and discuss how each of these processes impact both normal development and tumor suppression. To achieve this goal, the meeting assembles a broad spectrum of speakers whose interests span a variety of model organisms. The Keynote Speaker, Craig Thompson, will discuss the relationship between metabolic status and cell survival. This meeting will be held in conjunction with "Cell Death in the Immune System". Joint sessions will include the core apoptotic machinery, cell death and cellular homeostasis, signaling and apoptosis, and autophagy, inflammation and apoptosis. [unreadable] [unreadable] [unreadable] [unreadable]